Identification of alpha 2-adrenergic receptor sites in human retinoblastoma (Y-79) and neuroblastoma (SH-SY5Y) cells

Journal Article · Wed Feb 15 04:00:00 EST 1989 · Biochem. Biophys. Res. Commun.; (United States)

DOI:https://doi.org/10.1016/0006-291X(89)92810-6· OSTI ID:6075955

Kazmi, S M; Mishra, R K

The existence of specific alpha 2-adrenergic receptor sites has been shown in human retinoblastoma (Y-79) and neuroblastoma (SH-SH5Y) cells using direct radioligand binding. (/sup 3/H)Rauwolscine, a selective alpha 2-adrenergic receptor antagonist, exhibited high affinity, saturable binding to both Y-79 and SH-SY5Y cell membranes. The binding of alpha 1 specific antagonist, (/sup 3/H)Prazocine, was not detectable in either cell type. Competition studies with antagonists yielded pharmacological characteristics typical of alpha 2-adrenergic receptors: rauwolscine greater than yohimbine greater than phentolamine greater than prazocine. Based on the affinity constants of prazocine and oxymetazoline, it appears that Y-79 cells contain alpha 2A receptor, whereas SH-SY5Y cells probably represent a mixture of alpha 2A and alpha 2B receptors. alpha 2-agonists clonidine and (-)epinephrine inhibition curves yielded high and low affinity states of the receptor in SH-SY5Y cells. Gpp(NH)p and sodium ions reduced the proportion of high affinity sites of alpha 2 receptors. These two neuronal cell lines of human origin would prove useful in elucidating the action and regulation of human alpha 2-adrenergic receptors and their interaction with other receptor systems.

• Research Organization: McMaster Univ., Hamilton, Ontario (Canada)
• OSTI ID: 6075955
• Journal Information: Biochem. Biophys. Res. Commun.; (United States), Journal Name: Biochem. Biophys. Res. Commun.; (United States) Vol. 158:3; ISSN BBRCA
• Country of Publication: United States
• Language: English

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ALKALI METALS
ANIMAL CELLS
ANIMALS
AUTONOMIC NERVOUS SYSTEM AGENTS
BIOCHEMICAL REACTION KINETICS
CELL CONSTITUENTS
CELL MEMBRANES
DRUGS
ELEMENTS
KINETICS
LABELLED COMPOUNDS
MAMMALS
MAN
MEMBRANE PROTEINS
MEMBRANES
METALS
ORGANIC COMPOUNDS
PRIMATES
PROTEINS
REACTION KINETICS
RECEPTORS
SODIUM
SYMPATHOLYTICS
SYMPATHOMIMETICS
TRITIUM COMPOUNDS
TUMOR CELLS
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